Friendship draining - need help

Ok my friend is going through a break up and of course she is confiding and venting to me and that's cool, that's what friends are for. My issue is I guess I'm exhausted. For over a year now I've listened to her complain about her bf and his irritating habits and how she feels they need to break up. Well now that has happened and she's so upset by it (I think he said some things that were hurtful, which he apologized for). I feel like there's a lot of mixed emotions from I think we need to break up and I can't think straight with him here to I think he's a great guy and I want to see him do well and I know I have stuff to work on too. It's hard for me to give advice and then have my  friend flips the script and brings up contridictory thoughts that seem to counteract my advice or assessment of the situation. My friend and I are like sisters so I will continue to be there for her and listen as much as possible. But sometimes it is draining to rehash stuff over and over and over for hours!! How have you all helped friends in the past that are going through a tough break up and how do you  make sure your friends problem doesn't become yours? I feel like I'm going to end up shouldering some of her grief or her stress ... And that isn't because of her that's something I personally need to work on not allowing other pols problems become my own.